Challenge

Roof challenge

JJyotiprakash Das7 Aug 2022

ROOF DESIGN

An automobile roof or cap top is the portion of an automobile that sits above the passenger compartment protecting the vehicle occupants from sun, wind, rain and other external elements.

CAR ROOF

The automobile roof consists of the following parts-

The outer panel
Front roof rail
Bow roof
Center Roof Rail
Rear Roof Rail

Front Roof Rail-

The front roof rail is created at the front side of the roof to provide strength to the roof. Headroom clearance and driver visibility are the two important factors to be considered while designing the front roof rail. the front roof rail. the front roof rail is connected to the roof outer panel with the help of a mastic seal.

Bow Roof-

It is used to give strength to the area between the front roof and the center roof rail. Also, it is created in the area between the center roof rail and the rear roof rail to provide enough strength. It can create in any numbers depending on the bow roofs is to be justified by curvature study.

Center Bow Roof-

It is created at the center of the roof. it is connected to the roof by a mastic seal.

Rear Roof Rail-

It is created at the rear end of the roof. The fitment of the backdoor is to be considered while designing the rear roof rail.

ROOF IMAGES

HEAT DISTORTION CRITERIA:

Heat distortion temperature is the temperature at which metal softens and deforms under a specified load. While designing a roof, this criterion is taken into consideration. We create bow roofs when the roof is long and flat to increase strength. the position of the bow roofs is to be justified and this justification is done by curvature study.

Bow_Roof Prediction Formula-

TO MEASURE Ly

TO MEASURE Rx AND Ry

HEAT DISTRIBUTION CRITERIA

Here we can see that the position of the front bow roof is in the wrong position which needs to change.

SNOW LOAD PREDICTION FORMULA-

Snow load is the downward force on a car by the weight of accumulated snow and ice. The roof can fail if the snow load exceeds the weight the roof was designed to shoulder or if the roof was poorly designed or constructed.

So there is a formula to predict the strength of the load-

TO MEASURE Ly

TO MEASURE Lx

TO MEASURE Rx AND Ry

SNOWED CRITERIA

It is observed that the roof is satisfying the condition only in the area between the front roof rail and center bow roof.

In other areas it is not satisfying the condition. So in order to strengthen the roof at these areas emboss are created on the outer roof.

SECTION MODULUS STUDY OF THE SECTION OF THE ROOF RAILS-

The section modulus of the crossectional shape is of significant importance in designing of structures. It is a direct measure of the strength of the structure.

A structure that has a larger section modulus than another will be stronger and capable of supporting greater loads.

SECTION MODULUS (S) = I/Y

I- Moment of inertia

Y- Distance between the neutral axis and the extreme end of the object.

FRONT ROOF RAIL